Anyone else follow the practice of writing links knowing that one day others will follow the link and write the topic later?

I have this problem: I leave dangling links but I want the person who writes the topic to select which web (Section) the topic should reside in, rather than just let it end up in the current web.

For those who don't use FindElsewherePlugin any solution would have to also rewrite the resulting link.

I know I could write Web.TopicName rather than just TopicName but often I don't know at the time of writing which web would be best. (e.g. I'm studying Economics, Corporate Finance and Accounting and I don't have enough knowledge in advance to figure which one to put it in.)

Yes, I also use a lot of dangling links. That's how I create most content: put up some information with lots of wikiword links to nonexisting pages, and come back later to create these secondary pages when it's convenient -- and hope that possibly somebody else beat me to it. (Usually nobody beats me to anything in our TWiki, but that's a question of getting more buy in :-))

I also prefix my dangling links with the appropriate web name if it's = the current web. Mostly I know what other web that would be though, so I don't have a problem as you describe. If the target web is not known, I recommend just leaving out the prefix in the first place. You can always come back and tidy up/move pages around later.